Discharge luminescence element array having a gas flow path

ABSTRACT

A discharge luminescence element array comprising a pair of parallel insulating plates and a separator entirely sealed between the pair of insulating plates in which a groove-like gas flow path is provided between one of the plates and the separator for evacuating and providing gas from and to discharge spaces defined by the separator and the pair of insulating plates.

United States Patent 1 91 1111 3,869,630 Maio Mar. 4, 1975 [5 1DISCHARGE LUMINESCENCE ELEMENT 3.600626 8/1971 Kupsky 1. 313/220 s F WPATH 3.689.910 9/1972 Glaser t v 1 313/220 X ARRAY HAVHYG A G LO n1704386 11/1972 Cola 1 315/169 TV X [75} Inventor: Kenii M io, o bu iJapa 3,766,420 10/1973 Ogle ct 111. 313/1095 [73] Assignee: Hitachi,Ltd., Tokyo, Japan [22] Filed: 1973 Primary Erunziner-Siegfried H. Grimm211 App]. 339 91 Attorney, Agent, or Firm-Craig & Antonelli [30] ForeignApplication Priority Data Mari 13. 1972 Japan 47-25638 ABSTRACT [52]U.S.Cl .1313/188,313/2O1 3l3/210,

313/230 313/221 A discharge luminescence element array comprismg a 1511110. C1 HOlj l/78, H01 j 11/02 p of parallel insulating Plates and aseparator 5 Field f Search 313/1095 201 210 220 tirely sealed betweenthe pair of insulating plates in 313/221 133; 315/1 9 Rv 169 340/334which a groove-like gas flow path is provided between M, 1 R, 1 EL oneof the plates and the separator for evacuating and providing gas fromand to discharge spaces defined by 5 References Ci the separator and thepair of insu1ating plates.

UNITED STATES PATENTS 3509,4117 4/1970 C1111is.Jr 313/220 X 12 Claims, 5Drawing Figures 1 2/1 lva gzlq l r 7 Y 7 f 1 1 I 1:1 A /1 9 7 1 11 1 14- -l3 1 T* 1" I '1 I4 18' 1 FIG. 4 H '8 DISCHARGE LUMINESCENCE ELEMENTARRAY HAVING A GAS FLOW PATH FIELD OF THE INVENTION The presentinvention relates to a structure of a discharge luminescence elementarray and more particularly to a structure of a discharge luminescentelement array for minimizing light leakage or optical cross-talk betweenluminescent elements.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of aconventional switching matrix comprising a discharge luminescent elementarray and a photoconductive element array.

FIG. 2 is a cross-sectional view of a conventional arrangement forpreventing light leakage or optical crosstalk between the luminescentelements of the discharge luminescent element array.

FIGS. 3a and 3b are plan and cross-sectional views, respectively, of adischarge luminescent element array according to the present invention.

FIG. 4 is a diagram for explaining the path of light leakage between theluminescent elements of the discharge luminescent element array of FIGS.3a and 3b.

DESCRIPTION OF THE PRIOR ART Referring to FIG. 1, an arrangement isknown comprising a discharge luminescent element array 1 and aphotoconductive element array 2 in which the photoconductive elementarray 2 acts as a switch and the discharge luminescent element array 1acts as a driver therefor. The discharge luminescent element array 1consists of an insulator plate 11 having thereon transparent orsemi-transparent electrodes 10, a separator 12 having discharge spaces13 formed therein, and an insulator plate 14 having thereon transparentor semitransparent electrodes 15. If there occurs light irradiation oroptical cross-talk between adjacent luminescent elements of thedischarge luminescent element array 1, it disadvantageously reduces theresistance of the corresponding photoconductive element at the switchedoff time.

As an example of the discharge luminescence element array in whichoptical cross-talk is reduced to as low a degree as possible there isknown a type in which the opaque separator 12' is formed into comb-likeconfiguration as shown in FIG. 2. This separator can be provided on theinsulator plates 11 and 14 by, for example, a printing methocLHowever,since it is necessary for the separator to be printed with a highaccuracy of several tens of microns when the spacing between theluminescence elements is low, the provision of the separator by thismethod is practically difficult.

SUMMARY OF THE INVENTION The present invention is intended to overcomethe above disadvantage of the prior art arrangement.

An object of the present invention'is to provide a discharge luminescentelement array in which optical cross-talk between discharge luminescentelements is much reduced and which is simple in structure.

DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiiment of the dischargeluminescent element array according to the present invention isillustrated in FIGS. 3a and 3b in plan and elevational crosssectionalviews, respectively. The discharge luminescent element array comprises apair of parallel insulator plates 11 and 14, a separator 12" interposedbetween the pair of insulating plates 11 and 14, and electrodes l0 and15. A gas flow path 17 of any shape, for example a zigzag gas flow path,is provided to the sparator 12" and/or the insulator plate 11 or 14. Theplates 11 and 14 and the separator 12" are sealed together by cement,for example a glass material, to define discharge spaces 13.

The glass material used for the cement 18 is commonly formed byoverlaying a mixture liquid of glass powder, nitrocellulose and itssolvent, for example carbitol acetate, on the plates 11 and 14 orseparator 12" by, for example, a printing method and by firing, at whichtime the carbon in the nitrocellulose is partially separated togenerally turn the cement pale grey.

The degree of optical cross-talk between the luminescent elements due tothe light transmission through the glass material 18 will next becalculated referring to FIG. 4 which is an enlarged view of a part ofthe luminescent element array between two adjacent luminescent elementsshown in FIG. 3b. Denoting the intensity of incident light by Po, theintensity of transmitted light by Pt, and the distance between twoadjacent luminescent elements by t, and putting the photo-penetratingpower at r= r, as T (Pt) /Po) and that at r= r as T (Pr) /Po), T is given by T =(T )'2"1l Since the photo-penetrating power of glass materialat about 50 microns is commonly of the order of 40 to percent, theoptical cross-talk or light leakage between two luminescent, elements,i.e., the photopenetrating power T can be provided by putting thedistance I between two luminescent elements approximately at 2 Forexample, for T 70 percent, 1 50 ,u, and t 2 mm, T is given by T z 10'from Equation (I). This is a very small value. Thus, the amount of lightirradiation-or light leakage to the adjacent luminescent element canmarkedly be reduced by employing a material of a suitable lightattenuation as a cement.

If the separator 12 is entirely sealed to the plates 11' and 14, thedischarge spaces 13 are made airtight so that the gas in the dischargespaces cannot be evacuated nor can the discharge spaces be filled withany discharge gas. For this reason it is necessary to provide thedischarge spaces 13 with the gas flow path '17. It is effective for thegas flow path to be formed into a narrow zigzag groove shape to give alight shielding effect.

As a practical example, for the transparent glass plates 11 and 14 eachhaving a thickness of 0.3 mm, the separator 12" of a glass filter havinga high photoabsorptive power (Corning glass filter No. 7-56; TradeMark), and the spacing between adjacent two luminescent elements of a2.5 mm, the light leakage is about l0. On the other hand, when theseparator 12" is not entirely sealed, but sealed only at its peripheralportion, the light leakage or optical cross-talk is about 5 X 10. Thus,the present invention can reduce the optical cross-talk to aboutone-fiftieth or less.

The reason why the degree of the optical cross-talk in the abovepractical example is considerably higher than the calculated value isthat light is transmitted through the glass plates 11 and 14 rather thanthrough the cement 18. Consequently, by employing filter glass plateshaving a suitable photo-absorptive power as theinsulator plates 11 and14 the optical cross-talk could be reduced to the order of thecalculated value.

Though in FlGS. 3a and 3b the gas flow path 17 between adjacent twodischarge spaces 13 is a segmental line having only one break point, itcan advantageously have a number of break points. However, if so high alight attenuation is not required, the gas flow path 17 can be made astraight line having no break point.

' lclaim:

1. In a discharge luminescence element array comprising a pair ofparallel insulator plates, electrodes provided on the outer faces ofsaid pair of insulator plates, and a separator interposed between saidpair of insulator plates, said separator having a plurality of aperturesformed therein defining the same plurality of discharge spaces with saidpair of insulator plates, the improvement comprising a groove-likegasflow path provided at the interface between one of said pair ofinsulator plates and said separator for evacuating gas from andproviding a discharge gas to said discharge spaces, said separator beingsealed at its entire main faces to said pair of insulator plates.

2. A discharge luminescence element array according to claim 1, in whichsaid gas flow path between ad-v jacent discharge spaces is a zigzagsegmental line.

3. A discharge luminescence element array according to claim 1,'in whicheach of said insulator plates is a filter glass plate.

4. in a discharge luminescence element array comprising:

a pair of spaced apart insulator plates;

electrodes provided on the outer faces of said pair of insulator plates;

a separator interposed between the inner faces of said pair of insulatorplates, said separator having a plurality of apertures formed thereindefining a plurality ofdischarge spaces confined between said insulatorplates, which discharge spaces terminate at said inner faces of saidinsulator plates; and

a gas flow path provided through said separator so as to provide a fluidconnection between said discharge spaces;

the improvement comprising means for sealing said separator at therespective interfaces thereof with said inner faces of said pair ofinsulator plates comprising a light absorbent cement.

5. The improvement according to claim 4, wherein said gas flow pathcomprises an aperture interconnecting respective individual ones of saiddischarge spaces with each other, the cross-section of said aperturebeing considerably less than the cross-section of said discharge spaces.

6. The improvement according to claim 4, wherein each of said insulatorplates contains a filter glass material, said separator is made of aglass filter material having a high photoabsorptive power, and saidcement is substantially opaque.

7. The improvement according to claim- 6, wherein said gas flow pathcomprises an'aperture interconnecting respective individual ones of saiddischarge spaces with each other, the cross-section of said aperturebeing considerably less than the cross section of said discharge spaces.

8. The improvement according to claim 6, wherein said gas flow path hasa configuration which prevents direct linear optical communicationbetween adjacent discharge spaces.

9. The improvement according to claim 8, in which said gas flow pathbetween adjacent discharging spaces is a zigzag segmental line.

10. In a discharge luminescence element array comprising:

a pair of spaced apart insulator plates;

electrodes provided on the outer faces of said pair of insulator plates;a separator interposed at and sealed between the inner faces of saidpair of insulator plates, said separator having a plurality of aperturesformed therein defining a plurality of discharge spaces confined betweensaid insulator plates; and a gas flow path provided through saidseparator so as to provide a fluid connection between said dischargespaces;

the improvement wherein said gas flow path between adjacent pairs ofdischarge spaces follows a path which prevents direct opticalcommunication between the adjacent discharge spaces connected thereby.

11. The improvement according to claim 10, wherein the gas flow pathbetween an adjacent pair of discharge spaces follows a zig-zag path.

12. The improvement according to claim 10, wherein said separator issealed at the respective interfaces thereof with the inner faces of saidpair of insulator plates by a light absorbent cement.

1. In a discharge luminescence element array comprising a pair ofparallel insulator plates, electrodes provided on the outer faces ofsaid pair of insulator plates, and a separator interposed between saidpair of insulator plates, said separator having a plurality of aperturesformed therein defining the same plurality of discharge spaces with saidpair of insulator plates, the improvement comprising a groove-like gasflow path provided at the interface between one of said pair ofinsulator plates and said separator for evacuating gas from andproviding a discharge gas to said discharge spaces, said separator beingsealed at its entire main faces to said pair of insulator plates.
 2. Adischarge luminescence element array according to claim 1, in which saidgas flow path between adjacent discharge spaces is a zigzag segmentalline.
 3. A discharge luminescence element array according to claim 1, inwhich each of said insulator plates is a filter glass plate.
 4. In adischarge luminescence element array comprising: a pair of spaced apartinsulator plates; electrodes provided on the outer faces of said pair ofinsulator plates; a separator interposed between the inner faces of saidpair of insulator plates, said separator having a plurality of aperturesformed therein defining a plurality of discharge spaces confined betweensaid insulator plates, which discharge spaces terminate at said innerfaces of said insulator plates; and a gas flow path provided throughsaid separator so as to provide a fluid connection between saiddischarge spaces; the improvement comprising means for sealing saidseparator at the respective interfaces thereof with said inner faces ofsaid pair of insulator plates comprising a light absorbent cement. 5.The improvement according to claim 4, wherein said gas flow pathcomprises an aperture interconnecting respective individual ones of saiddischarge spaces with each other, the cross-section of said aperturebeing considerably less than the cross-section of said discharge spaces.6. The improvement according to claim 4, wherein each of said insulatorplates contains a filter glass material, said separator is made of aglass filter material having a high photoabsorptive power, and saidcement is substantially opaque.
 7. The improvement according to claim 6,wherein said gas flow path comprises an aperture interconnectingrespective individual ones of said discharge spaces with each other, thecross-section of said aperture being considerably less than the crosssection of said discharge spaces.
 8. The improvement according to claim6, wherein said gas flow path has a configuration which prevents directlinear optical communication between adjacent discharge spaces.
 9. Theimprovement according to claim 8, in which said gas flow path betweenadjacent discharging spaces is a zigzag segmental line.
 10. In adischarge luminescence element array comprising: a pair of spaced apartinsulator plates; electrodes provided on the outer faces of said pair ofinsulator plates; a separator interposed at and sealed between the innerfaces of said pair of insulator plates, said separator having aplurality of apertures formed therein defining a plurality of dischargespaces confined between said insulator plates; and a gas flow pathproVided through said separator so as to provide a fluid connectionbetween said discharge spaces; the improvement wherein said gas flowpath between adjacent pairs of discharge spaces follows a path whichprevents direct optical communication between the adjacent dischargespaces connected thereby.
 11. The improvement according to claim 10,wherein the gas flow path between an adjacent pair of discharge spacesfollows a zig-zag path.
 12. The improvement according to claim 10,wherein said separator is sealed at the respective interfaces thereofwith the inner faces of said pair of insulator plates by a lightabsorbent cement.